Method and mechanism for opening and closing of manhole covers

ABSTRACT

A cover for opening and closing a manhole includes a movable cover and a base cover, the movable cover and the base cover being connected to each other by a shaft manufactured from an aluminium bronze alloy that passes through at least one first hinge part fastened to the movable cover and at least two second hinge parts fastened to the cover base, the first hinge part being fastened perpendicularly to the second hinge parts. In this way, it is possible to manufacture robust manhole covers offering good comfort to a driver of a car, since the movable cover may be manufactured so that the distance between an outer rim of the movable cover and the base cover is minimized.

The invention relates to a method of fastening including hinging, opening and closing of manhole covers, such as manhole covers in relation to cover bases such as entrance openings for sewer- or waste water line inspection wells.

The invention furthermore relates to a mechanism for opening and closing covers such as manhole covers placed on cover bases such as openings for sewer- or waste water line inspection wells.

Covers such as so-called manhole covers are typically used at entrance openings of inspection wells by waste water mains, which are often placed in roads.

The techniques, which have hitherto been used for handling these cover types, including opening and closing them, typically includes opening and closing of lids, where the whole edge of the cover periphery is in contact with the cover base, when the cover is closed.

The covers are furthermore typically hinged in relation to the cover base with relatively large and voluminous hinges, which carry the weight of the cover, when the covers are opened.

It has been found, however, that this prior art involves some drawbacks.

One of these drawbacks concerns the principle with which the closing is made, which involves contact with relatively large surface areas between the cover and the cover base.

If the cover is going to close properly in relation to the cover base, it is obviously a precondition that the areas of contact between the two means are clean, when the manhole cover is closed.

In practice it has meanwhile been found that it is often a problem that the areas of contact are not sufficiently cleaned before the covers are closed.

This means that the covers can tilt, when they are subjected to load of e.g. trucks or other heavy vehicles, which drive on the covers.

When the covers tilt, they will typically emit noise, which can be a nuisance for nearby residents, and the covers and the hinges can be damaged, resulting in expensive costs.

Another drawback of the known techniques is caused by the mentioned large hinges, which are typically used in the known manhole covers.

Large hinges generally demand large rotational movements, which means that there must be a relatively large distance between the cover and the cover base in the direction of the hinges, of the sole reason that there must be room for the cover to turn in the hinges.

This results in the drawback that there will be a wide crack between the cover and the cover base, which decreases the quality of the road, including the driving comfort for the road users, and the crack can be filled with filth and dirt, which can create problems when the cover is to be opened.

It is therefore a purpose of the invention to improve the known method and mechanism for opening and closing manhole covers.

The object of the invention is achieved by a method of the type staled in the introductory portion of claim 1, which is characterized in that the fastening is established through one or several, preferably four connecting devices and through one or more, preferably two hinges.

Hereby, it thus becomes possible to reduce the area, which constitutes the area of contact between the cover and the cover base, when the manhole cover is closed, to solely consist of the areas of contact between the connection devices.

This includes the positive characteristic that the cleaning in connection with closing of covers is reduced to cleaning the small areas of contact in the connection devices.

As a result of the simplified cleaning procedure, a great number of correct cover closings is hereby achieved and the inconveniences and costs of maintenance are also reduced in the same extent.

As stated in claim 7 it is furthermore a particular characteristic of the invention that the hinge consists of one or several, preferably two lower parts, which is integrated in the cover base, and one or more, preferably one top device, which is integrated in the cover, where lower part and upper part is connected through a transverse shaft manufactured of an aluminium bronze alloy, and where the material thickness of the hinge parts between the shaft and the cover in the direction of the cover is smaller than the shaft's cross-sectional diameter, preferably smaller than 0.3 times the cross-sectional diameter of the shaft.

Hereby, it is achieved that the crack between the manhole cover and the cover base can be reduced, which improves the quality of the road surface and reduces the problems of filth aggregation.

Further appropriate embodiments of the method are stated in claims 2 to 6.

As mentioned, the invention also relates to a mechanism.

This mechanism is characterized in that the mechanism consists of one or more, preferably four connection devices placed in the periphery, such as in the corners of the cover and cover base with top parts in the cover and lower parts in the cover base, where closing is done by screwing together the top- and lower part by activating a bolt integrated in the top part.

Hereby it is achieved that it becomes possible to manufacture covers, which are simple to use and maintain, and thus only demands low costs of maintenance.

The invention will now be explained more fully with reference to the drawings, in which:

FIG. 1 shows a cover closed over a cover base.

FIG. 2 shows a manhole cover opened in relation to a cover base.

FIG. 3 shows a section of an open cover with clarified connection device and hinge.

FIG. 4 shows, in a cross section, an assembled connection device.

FIG. 5 shows, in a cross section, a separate connection device.

FIG. 6 shows, seen from the side, a simplified sketch of a hinge.

FIG. 7 shows, seen from above, a simplified sketch of the same hinge, which is FIG. 6 seen from the side.

In FIG. 1 is with 1 indicated, shown a cover, which is closed into a cover base 2. The cover 1 is fastened to the base 2 by bolts 3, which are screwed into it from the top of the cover 1.

The base 2, in the shown photo, consists of a mounting base, which is used for product presentation, but will in practice typically be inserted into a road, where the cover 1, thus e.g. can cover the entrance opening to a waste water line inspection well.

In FIG. 2, the cover 1 is open in relation to the cover base 2, and as it appears from FIG. 2, the bolts 3 are now screwed up. The bolts 3 are placed in the top part 4 of the connection devices, which furthermore consists of lower parts 5. Each bolt 3 is thus mounted in a top part 4, which by closing the cover 1 touches a lower counter part 5, which is provided with a thread for screwing in the bolt 3.

The cover unit is furthermore provided with a safety device 6, which maintains the cover 1 in the opening position, and a feather 7, which has the purpose of ease the opening of the cover 1.

FIG. 3 shows a sectional view of a corner of an open manhole cover 1, which is hinged in relation to the cover base 2 with a hinge 10, where the hinge 1 can turn freely around the transverse shaft 11. The cover 1 is in the corner provided with the top part 4 of a connection device, where the threaded end of the bolt 3 is clearly seen. The connection device 4 is provided with a hole 8, through which a pin can be put into the bolt 3, for blocking the movement of the bolt.

In FIG. 3 is furthermore shown the connection device's lower part 5, which is provided with a hole in the thread 9, in which the bolt 3 can be screwed into when the manhole cover is closed.

When the cover 1 is closed, the area of contact between the cover 1 and the cover base 2 consists solely of the areas of contact between the connection devices' top 4 and bottom 5.

It is thus solely these small areas, which must be cleaned in advance of closing a cover, in order to secure a perfect cover closing.

In FIG. 4 is shown a cross section of an assembled connection device, which consists of a top part 4, which is integrated in the cover, and a lower part 5, which is integrated in the cover base.

The bolt 3 is in the bottom provided with a thread 14, in which a complementary thread part 15 can be screwed into, in the lower part 5.

In a preferred embodiment, the thread part 15 consists of a so-called helicoil insert.

The top part 4 is provided with holes 8, through which a blocking device such as a pin 13 can be inserted in the bolt 3. The pin 13 thus prevents that the bolt 3 can be lifted up from the top part 4.

The bolt 3 is in the top provided with a blocking device such as a pin, disc or collar 19, which prevents the bolt 3 from moving further towards the lower part 5 than shown in FIG. 4.

A spring 12 prevents that the bolt 3 is lifted free from the top, when it is screwed away from the lower part 5, whereby it is easily operated by screwing it back in.

As it will appear from FIG. 4, the area of contact between the top 4 and the lower part 5 is small, and is therefore easily cleaned.

In FIG. 5 is shown a cross section of a disassembled connection device consisting of a top part 4, which is in the shown example detached and disassembled from a lower part 5.

The bolt 3 is lifted free from the top part 4 through the use of the spring 12, but is prevented from being attached from the top part 4 by the pin 13.

A subsequent correct closing of the two items 4 and 5 therefore only demands that the surface between the items is clean.

In FIG. 6 is shown, seen from the side, a simplified sketch of a hinge according to the invention where the hinge 1 can turn freely around the axis of centres for the shaft 11, and thereby be turned from the shown horizontal position to a vertical position

As it will appear from FIG. 6, there is only a minimal material thickness of the hinge part 10, which is fastened to the cover base 2, between the shaft 11 and the cover 1.

In a preferred embodiment, the material thickness is significantly smaller than the diameter of the shaft 11, the thickness is thus smaller than 0.3 times the diameter of the shaft.

Hereby, it is achieved that the width of the gap 20 can be minimized, resulting in advantages for the comfort of driving on the road where the cover is mounted and less chances of accumulation of filth.

In FIG. 7 is shown, seen from the side, a simplified sketch of the same hinge, which in FIG. 6 is seen from the side.

As it will appear from FIG. 7, the hinge can in a preferred embodiment consist of two parts 10, which are fastened to the cover base 2, and a part 16, which is fastened to the cover 1.

The mounting 16 and thereby the cover 1 can be turned around the shaft 11. Tests have shown that shafts manufactured of so-called aluminium bronze alloys have particularly desirable bearing characteristics, while the additional hinge parts with advantage can be manufactured of a robust and cheap metal such as iron.

The shaft 11 is fastened to the hinge parts 10 e.g. by inserted tailstock screws 18, and can be lubricated via an inserted lubricator nipple 17, mounted in the hinge part 16.

With the invention, it has become possible to manufacture covers, including so-called manhole covers, in a way so they become robust, easy to operate, environmentally benign and have low costs of maintenance.

The invention is not limited to the embodiments, which can directly be derived from the present description and the present drawings, but also includes all embodiments, which indirectly can be derived from the description and the drawings or by a combination of these. 

1-8. (canceled)
 9. A cover adapted to opening and closing a manhole, said cover consisting of a movable cover (1) and a base cover (2), said movable cover being connected to the cover base by a shaft (11), wherein the shaft (11) is passed through at least a first hinge part (16) fastened to the movable cover (1) and passed through at least two second hinge parts (10) fastened to the cover base (2), said first hinge part being fastened perpendicular relative to the two second hinge parts.
 10. A cover according to claim 9, wherein two shafts (11) are passed through two first hinge parts and four second hinge parts.
 11. A cover according to claim 9, wherein the second hinge parts are formed by two legs that are perpendicular relative to each other.
 12. A cover according to claim 9, wherein the material thickness of the second hinge parts (10) between the shaft (11) and the movable cover in the direction of the movable cover is smaller than the cross-sectional diameter of the shaft.
 13. A cover according to claim 12, wherein the material thickness of the second hinge parts is smaller than 0.3 times the cross-sectional diameter of the shaft.
 14. A cover according to claim 9, wherein the shaft (11) is made of an aluminium bronze alloy. 